This invention relates to an intelligent robotic aid system for use in tracking and avoiding collision with an object, particularly for use in hospitals and homes. In particular, this invention relates to a robotic aid system which can be used, for instance, to assist the physically disabled user in feeding. This system includes a machine-vision subsystem that tracks the position of an object, such as a person's face, in real time and provides for reflex action.
Hammel et al., J. Rehabilitation Res. & Dev., 26(3):1 (1988), estimate that caring for a quadriplegic veteran, including standard medical treatment, equipment maintenance, and attendant care, cost about $47,000 per year. This amounts to the net direct cost of approximately five billion dollars to the Department of Veterans Affairs for its current quadriplegic population. Engelberger, Robotics in Service, The MIT Press (1989), also estimates the cost for a case of spinal cord injury to be $57,000 per patient per year.
Several works, including Hammel et al.; Seamone et al., J. Rehabilitation Res. & Dev., 22(1):38 (1985); Kwee et al., First Int. Workshop on Robotic Applications in Medical & Health Care, Ottawa June 1988); Gan et al., Proceed. of the 22nd Southeastern Symposium on System Theory, Cookeville, Tenn. (March 1990); and Dijkers et al., J. Rehabilitation Res. & Dev., 28(2):33 (1991), have addressed this problem and demonstrated the feasibility of robotic approaches. Clinical evaluations of prototype robotic aid systems revealed positive acceptance of such systems by many of the users.
Two problems must be solved for a robot to feed a person. First, the robot must continually track the position of the person's face. Second, the robot must be able to get out of the way if the person moves suddenly. The first problem can be solved if the position of the person's face can be tracked in real time. The second problem requires reflex action on the part of the robot. Both problems require the ability to predict and follow human motion. The term reflex is used to denote reactive behaviors against unexpected events.
Because the robot arm operates near the human face, a control mechanism to avoid collision is an indispensable component of the system. In Hammel et al., the robot can be stopped by a voice command STOP, pressing a stop switch, or any loud noise. The instant invention relates to integrating these passive ways of stopping the robot with autonomous collision avoidance by the robot itself. Techniques needed for this purpose are real time face tracking, motion prediction, and reactive/predictive motion planning. Thus, the instant invention enhances the safety of a robotic aid system by allowing for the integration of multiple modalities such as vision, sound, touch-sensors, and switches.
Throughout this application, various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this invention pertains.